Find a basis and the dimension of the solution space of the homogeneous system
2x_{1} + x_{2} \ \ \ \ \ \ \ \ = 0 \\ x_{1} + x_{2} - x_{3} = 0 \\ \ \ \ \ -x_{2} + 2x_{3} = 0
Find a basis and the dimension of the solution space of the homogeneous system
2x_{1} + x_{2} \ \ \ \ \ \ \ \ = 0 \\ x_{1} + x_{2} - x_{3} = 0 \\ \ \ \ \ -x_{2} + 2x_{3} = 0
We found in Example 2.2.9 that the general solution of this system is
\vec{x} = t\left [ \begin{matrix} -1 \\ 2 \\ 1 \end{matrix} \right ] , \ \ \ \ t \in \mathbb{R}
This shows that a spanning set for the solution space is \mathfrak{B} = \left\{\left [ \begin{matrix} -1 \\ 2 \\ 1 \end{matrix} \right ] \right\}. Since B contains one non-zero vector, it is also linearly independent and hence a basis for the solution space. Since the basis contains 1 vector, we have that the dimension of the solution space is 1.